The use of peripheral perfusion index as a predictor for patient’s response to deliberate hypotension during functional endoscopic sinus surgery. A prospective observational study

Abstract

Background: Peripheral perfusion index (PPI) reflects changes in the vasomotor tone. The aim of this observational study is to explore the potentials of the PPI as a predictor of the response to nitroglycerin-induced hypotensive anesthesia in patients undergoing functional endoscopic sinus surgery (FESS). Methods: Forty-seven patients undergoing FESS were included. Deliberate hypotension was achieved using nitroglycerin infusion titrated to a mean arterial blood pressure (MAP) of 60–65 mmHg. PPI was recorded before induction of anesthesia (baseline), at: 1 minute after induction, 1 minute after endotracheal intubation and just before the initiation of nitroglycerin infusion. The correlation between PPI measured at different time points and the time and the dose requirements of nitroglycerin to achieve the target MAP were evaluated. Results: There was a significant positive correlation between the baseline PPI and the time to reach target MAP (r = 0.68, p < 0.0001), the infusion rate of nitroglycerin (r = 0.67, p < 0.0001) and the total intraoperative nitroglycerin consumption (r = 0.65, p < 0.0001). The baseline PPI was the only predictor of nitroglycerin requirement with a cut-off value of 2.8 and an area under the curve 0.85 (95%CI 0.71–0.94, P < 0.0001). The expected individualized dose requirements of nitroglycerin could be derived from the regression equation based on the baseline PPI value. Conclusion: Baseline PPI is a good predictor for the patients’ response to nitroglycerin-induced hypotensive anesthesia. Lower baseline PPI values are associated with a reduction in the time and the dose of nitroglycerin required to achieve and maintain the target MAP. Clinical trials.gov Identifier No: NCT03007355 Registered on 2 January 2017.